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At least 40 million people watched the ending of the manhunt for the Boston Marathon bomber Friday, according to Nielsen.

The 7 p.m. hour when the news broke saw 5.75 million viewers flock to Fox News Channel, giving it a win for the hour over CNN's 5.19 million and MSNBC's 1.43 million. CNN managed to pull off an atypical victory in the key demographic of adults 25-54 -- and by a healthy margin. The network averaged 2.36 million adults 25-54 in the hour, topping FNC's 1.57 million and MSNBC's 459,000.

Wall-to-wall coverage on the broadcast networks saw the peak 8 p.m. hour dominated by NBC News. The network averaged 10.7 million, besting ABC's 7.79 million and CBS' 6.89 million. Adding the cable networks' respective hauls of 7.65 million (FNC), 6.78 million (CNN) and 1.7 million (MSNBC) in that hour, manhunt viewership peaked with a total of 41.5 million. That doesn't even take into account the viewers watching coverage on HLN, Univision and online.

Viewers continued to flock to the three cable networks as more developments came in. Between 8 and 11 p.m., Fox topped the primetime block with an average 5.97 million viewers. CNN had 5.37 million, with MSNBC pulling in 1.72 million. CNN saw another win in the key demographic with 2.47 million adults, topping FNC's 1.93 million and MSNBC's 618,000. MSNBC was the only network not to peak in the 8 p.m. hour. It hit 2.06 million viewers at 9 p.m.

For the complete five-day week, cable news saw expected spikes in total day viewership. CNN jumped a massive 294 percent, week-to-week, from its third place status. The network averaged 1.43 million viewers. FNC, still tops by all measures, was up 78 percent to an average 1.93 million viewers. MSNBC lost its second place status to CNN but jumped 69 percent to an average 633,000 daily viewers.

All told, total cable news viewership was up an average 119 percent compared to the same five-day period for the week before.